Lennox ELITE Series Installation Instructions Manual page 21

Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated
NOTE - Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total.
Both Intake and Exhaust must be same pipe size.
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the
total vent length calculation
No Of 1-1/2" Pipe
90°
Model
Elbows
045 070 090 110 135 045
Used
1 20 15
2 15 10
3 10
4
5
n/a n/a n/a
6
n/a
7 n/a
8
9
10
No Of 1-1/2" Pipe
90°
Model
Elbows
045 070 090 110 135 045 070 090 110 135 045 070 090 110 135 045 070 090 110 135
Usedl
1 20 15
2 15 10
3 10
4
5
n/a n/a n/a
6
n/a
7 n/a
8
9
10
TABLE 6
Attic or Crawl Space For Intake Air in Feet
Standard Termination at Elevation 0 - 4500 ft
2" Pipe
Model
070 090 110 135
71 56 34 14
66 51 29 9
61 46 24 4
56 41 19
51 36 14
46 31 9
41 26 4 n/a
36 21
31 16 n/a
26 11
Standard Termination Elevation 4500 - 10,000 ft
2" Pipe
Model
71 56 34
66 51 29
61 46 24
56 41 19
51 36 14
n/a n/a
46 31 9
41 26 4
36 21
31 16 n/a
26 11
Page 21
2-1/2" Pipe
Model
045 070 090 110 135
100 100 78 43
95 95 73 38
90 90 68 33
85 85 63 28
80 80 58 23
n/a
75 75 53 18
70 70 48 13
65 65 43 8
60 60 38 3
55 55 33 n/a
2-1/2" Pipe
Model
100 100 78 43
95 95 73 38
90 90 68 33
85 85 63 28
80 80 58 23
75 75 53 18
70 70 48 13
65 65 43 8
60 60 38 3
55 55 33 n/a
3" Pipe
Model
045 070 090 110 135
118 117 98 98
113 112 93 93
108 107 88 88
103 102 83 83
98 97 78 78
n/a
93 92 73 73
88 87 68 68
83 82 63 63
78 77 58 58
73 72 53 53
3" Pipe
Model
118 117 98 98
113 112 93 93
108 107 88 88
103 102 83 83
98 97 78 78
n/a
93 92 73 73
88 87 68 68
83 82 63 63
78 77 58 58
73 72 53 53
94
89
84
79
74
69
64
59
54
49
94
89
84
79
74
69
64
59
54
49